Boston's Fenway Community Heath Center (FCHC), in collaboration with Brown University in Providence, RI, is applying to become an HIV Prevention Trials Unit (HPTU), building on longstanding successful collaborations as the New England HIVNET unit. The clinical sites for this HPTU will include a) FCHC; b) Brown University, including its teaching hospitals, the Memorial, Miriam, and Women and Infants Hospitals; and c) Brown's Fogarty AIDS International Training and Research Program affiliate in Chennai, India, an NGO, YR Gaitonde Center for AIDS Research and Education (YRGCare). The HPTU will actively participate with the Scientific Leadership Group development, implementation and recruitment for the following studies to: 1) enroll 50 HIV(-)low risk women, 15-20 of their HIV(-)low risk male partners, and 20 HIV-infected women in 3 different Phase I vaginal microbicide studies; 2) enroll 100 HIV(-) high risk women in Rhode Island and 100 HIV(-) high risk women in Chennai in a Phase IIB microbicide screening trial; 3) continue to follow the 720 men recruited at FCHC into explore!, the behavioral intervention for MSMs; 4) enroll 500 HIV(-) high risk women in a Phase IIB behavioral intervention; 4) enroll 30 couples (heterosexual or MSM) to study the effects of antiretroviral therapy on genital tract HIV and transmission dynamics; 5) enroll 50 active IDUs from Rhode Island in Phase I studies to assess strategies that will alter needle sharing behavior, and; 6) enroll 50 HIV-infected pregnant women in year I and 100 mother/infantpairs in each of the following years in Chennai in a multicenter study of newer antiretroviral regimens designed to interrupt perinatal transmission. Additionally, we will participate in the STD Scientific Working Group to develop new protocols relevant to the populations studied in each of the major participating sites of our consortium. We will continue our leadership work in community education and the engagement of diverse communities in HIV prevention initiatives. (